1674
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 3840
- Proper Divisor Sum (Aliquot Sum)
- 2166
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 540
- Möbius Function
- 0
- Radical
- 186
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 3
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 42
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Appears in sequences
- Numbers that are the sum of 3 nonnegative cubes in more than 1 way.at n=11A001239
- Least k such that H(k) > n, where H(k) is the harmonic number Sum_{i=1..k} 1/i.at n=8A002387
- Least k such that H(k) >= n, where H(k) is the harmonic number Sum_{i=1..k} 1/i.at n=8A004080
- Numbers k such that if 2 <= j < k then the fractional part of the k-th partial sum of the harmonic series is < the fractional part of the j-th partial sum of the harmonic series.at n=4A004796
- a(n) = 1 + L(n) + F(2*n-1) with {L(n)}_{n>=0} the Lucas numbers (A000032) and F(2*n-1)_{n>=0} the bisected Fibonacci numbers (A001519).at n=9A005522
- Inverse Moebius transform of triangular numbers.at n=49A007437
- Coordination sequence T2 for Zeolite Code VSV.at n=26A009915
- Numbers k such that the geometric mean of phi(k) and sigma(k) is an integer.at n=25A011257
- Number of books required for n book-lengths of overhang in the harmonic book stacking problem. Sum_{i=1..a(n)} 1/i >= 2n and Sum_{i=1..a(n)-1} 1/i < 2n.at n=3A014537
- Numbers k such that the continued fraction for sqrt(k) has period 24.at n=21A020363
- Numbers k such that Fibonacci(k) == -8 (mod k).at n=22A023166
- Numbers that are sums of 2 distinct positive cubes.at n=50A024670
- Index of 6^n within the sequence of the numbers of the form 4^i*6^j.at n=50A025714
- Index of 8^n within the sequence of the numbers of the form 5^i*8^j.at n=50A025729
- T(n,1) + T(n,2) + ... + T(n,n), T given by A026703.at n=9A026710
- Triangular array T read by rows: T(n,0)=T(n,n)=1 for n >= 0; T(2,1)=2; for n >= 3 and 1<=k<=n-1, T(n,k) = T(n-1,k-1) + T(n-2,k-1) + T(n-1,k) if 1<=k<=(n-1)/2, else T(n,k) = T(n-1,k-1) + T(n-1,k).at n=71A026769
- a(n) = T(2n-1,n-1), T given by A026769. Also T(2n+1,n+1), T given by A026780.at n=5A026773
- a(n) = T(n, floor(n/2)), T given by A026769.at n=11A026775
- Greatest number in row n of array T given by A026769.at n=11A027238
- a(n) = n^2 - 7.at n=38A028881